“We could see limbs down and the uprooting of trees,” says Bill Read, director of the National Hurricane Center in Miami. “If the roads are covered with trees, this could be a problem for responders if someone has an emergency.”

From the easternmost part of Long Island to Rhode Island and Cape Cod, Earl is expected to unleash wind gusts of 75 to 100 miles per hour, says meteorologist Mike Pigott of AccuWeather.com. In the eastern part of Cape Cod around Chatham, for example, the winds could reach a sustained 75 miles per hour.

On Thursday morning, the National Hurricane Center officially put southeastern Massachusetts – including Cape Cod, Nantucket, and Martha’s Vineyard – on hurricane warning status. That means the region can expect winds of at least 74 miles per hour, probably starting Friday evening.

With widespread wind damage, power outages can stretch for days or maybe even longer. “That is why we encourage people to have adequate supplies of food and water, so they can withstand maybe several days without electricity,” says Owen.

One indication of how long power outages can go: After Wilma, a powerful hurricane, roared through Florida in 2005, many residents went for more than two weeks without electricity.

That happened to Fort Lauderdale residents Karen and Peter Audet, who endured 15 days without electricity. All their food spoiled, and they could not watch television or use their computers, Ms. Audet recalls.

“We just had to talk to each other and go to bed early,” says Ms. Audet, adding, “We also got to know our neighbors better.”

Also, they had to collect water and ice every day from local churches.

On Cape Hatteras, which could get the worst of the storm, water damage could be a problem as well as wind issues. Mr. Pigott expects a storm surge of three to six feet and rainfall of two to four inches.

By the time the storm moves northeast to Cape Cod and Nantucket, the storm surge will be somewhat lessened – more in the three- to four-foot range, he estimates. Also, since the storm should be moving fast once it gets that far north, the water could recede relatively quickly.

According to Pigott, some wind damage could result from the strong cold front that is to follow Earl. Cooler winds gusting up to 35 miles per hour are expected to whip through the east on Saturday.

“In New York City, some of the strongest wind gusts will be from the cold front immediately following Earl,” he says.